Foreground simulations for the LOFAR-epoch of reionization experiment

By V. Jelić, S. Zaroubi, P. Labropoulos, R. Thomas, G. Bernardi, M. Brentjens, G. D. Bruyn, Benedetta Ciardi, G. Harker, Leon V. E. Koopmans and 3 more. 2008

225 citations recorded by the source corpus.

Future high-redshift 21-cm experiments will suffer from a high degree of contamination, due both to astrophysical foregrounds and to non-astrophysical and instrumental effects. In order to reliably extract the cosmological signal from the observed data, it is essential to understand very well all data components and their influence on the extracted signal. Here we present simulated astrophysical foregrounds data cubes and discuss their possible statistical effects on the data. The foreground maps are produced assuming 5 degrees x 5 degrees windows that match those expected to be observed by the LOFAR epoch of reionization (EoR) key science project. We show that with the expected LOFAR-EoR sky and receiver noise levels, which amount to approximate to 52 mK at 150 MHz after 400 h of total observing time, a simple polynomial fit allows a statistical reconstruction of the signal. We also show that the polynomial fitting will work for maps with realistic yet idealized instrument response, i.e. a response that includes only a uniform uv coverage as a function of frequency and ignores many other uncertainties. Polarized Galactic synchrotron maps that include internal polarization and a number of Faraday screens along the line of sight are also simulated. The importance of these stems from the fact that the LOFAR instrument, in common with all current interferometric EoR experiments, has an instrumentally polarized response.

Subfields: Astronomy and Astrophysics, Nuclear and High Energy Physics

View Paper: https://www.semanticscholar.org/paper/be3897f8239a1d6ae3395e0b7b410b5b8eb6b32e

How researchers see this paper

The researchers whose trusted networks rank it highest, strongest advocate first. Every researcher gets a different order.

In Astronomy and Astrophysics

In Nuclear and High Energy Physics

Citations in the corpus

A simulation-calibrated limit on the H i power spectrum from the GMRT Epoch of Reionization experiment (2013, background): “4, the solid yellow line represents the theoretical signal from Jelić et al. (2008).”
LATE-TIME COSMOLOGY WITH 21 cm INTENSITY MAPPING EXPERIMENTS (2014, methodology): “This is at the heart of the methods presented in Wang et al. (2006), Gleser et al. (2008), Jelić et al. (2008), and Liu et al. (2009).”
FOREGROUND CONTAMINATION IN INTERFEROMETRIC MEASUREMENTS OF THE REDSHIFTED 21 cm POWER SPECTRUM (2008, methodology): “…could control the spectral dependence of their array beam sidelobes by masking out regions of the uvplane that are not sampled at all frequencies and only processing regions that do have coverage in each spectral channel (as considered in Jelić et al. (2008) for the more sparsely sample LOFAR).”
Hydrogen Epoch of Reionization Array (HERA) (2016, methodology): “This was a conservative value based on estimates of power in spectrally smooth foreground sources (Santos et al. 2005; Ali et al. 2008; de Oliveira-Costa et al. 2008; Jelić et al. 2008; Bernardi et al. 2010) and experience with PAPER dealing with foreground systematics.”
Foregrounds for observations of the cosmological 21 cm line - I. First Westerbork measurements of Galactic emission at 150 MHz in a low latitude field (2009, methodology): “Several authors have simulated the properties of the fore-grounds in order to test strategies and algorithms to subtract or ﬁlter them from the data (Di Matteo et al. 2004; Morales et al. 2006; Gleser et al. 2007; Jeli´c et al. 2008; Liu et al. 2009a; Harker et al. 2009; Liu et al. 2009b).”
Improved upper limits on the 21 cm signal power spectrum of neutral hydrogen at z ≈ 9.1 from LOFAR (2020, background): “The emission of these foregrounds varies smoothly with frequency, and this characteristic can be used to differentiate it from the rapidly fluctuating 21-cm signal (Jelić et al. 2008).”
LOFAR: The LOw-Frequency ARray (2013, background): “The EoR power spectrum can be observed over about two orders of magnitude in wave numbers and other higher-order statistical measures can be obtained as well (Jelić et al. 2008; Harker et al. 2009, 2010; Labropoulos et al. 2009).”
An improved source-subtracted and destriped 408 MHz all-sky map (2014, background): “This should prove useful in simulations used for studying the feasibility of detecting HI fluctuations from the Epoch of Reionization.”
Post‐correlation radio frequency interference classification methods (2010, background): “For example, a diﬀerence in the observed noise level caused by RFI will be fatal for the LOFAR Epoch of Reionization experiment (Jeli´c et al. 2008).”
A PER-BASELINE, DELAY-SPECTRUM TECHNIQUE FOR ACCESSING THE 21 cm COSMIC REIONIZATION SIGNATURE (2012, background): “…many times in the literature, linear polarization measurements of emission with high rotation measure pick up the rapid rotation of polarization angle with frequency that is of concern for measuring 21cm reionization (Furlanetto et al. 2006; Jelić et al. 2008; Pen et al. 2009; Geil et al. 2011).”
BRIGHT SOURCE SUBTRACTION REQUIREMENTS FOR REDSHIFTED 21 cm MEASUREMENTS (2010, background): “…Lonsdale et al. 2009; Bowman et al. 2006), Precision Array to Probe Epoch of Reionization [PA-PER] (Backer et al. 2007; Parsons et al. 2009), Low Frequency Array [LOFAR] (Harker et al. 2010; Jeli´c et al. 2008; Labropoulos et al. 2009) and Giant Meterwave Radio Telescope [GMRT] (Pen et al. 2009).”
PAPER-64 CONSTRAINTS ON REIONIZATION: THE 21 cm POWER SPECTRUM AT z = 8.4 (2015, background): “…where 21 cm reionization experiments operate, emission from these foregrounds is brighter than the predicted reionization signal by several orders of magnitude (Santos et al. 2005; Ali et al. 2008; de Oliveira-Costa et al. 2008; Jelić et al. 2008; Bernardi et al. 2009, 2010; Ghosh et al. 2011).”
Upper Limits on the 21 cm Epoch of Reionization Power Spectrum from One Night with LOFAR (2017, background): “In particular, Jelić et al. (2008), Harker et al. (2010) and more recently Chapman et al. (2013, 2016) have shown that despite the low signal-to-noise ratio and prominent Galactic and extragalactic foreground emission, the variance and power spectrum of the brightness temperature fluctuations of…”
Reionization and the Cosmic Dawn with the Square Kilometre Array (2012, methodology): “Jelić et al. (2008) made a first foreground model that includes both Galactic and extragalactic components of the foreground emission (see Figure 15). de Oliveira-Costa et al. (2008) used all publicly available total power radio surveys to obtain all-sky Galactic maps at the desired frequency…”
The GMRT Epoch of Reionization experiment: a new upper limit on the neutral hydrogen power spectrum at z≈ 8.6 (2010, background): “This signal would be more than an order of magnitude larger than the predictions by e.g. Iliev et al. (2008) or Jelić et al. (2008).”
Reionization and Cosmology with 21-cm Fluctuations (2009, methodology): “A number of techniques have been developed for fitting out the slowly varying foreground emission along each line of sight, including polynomials (McQuinn et al. 2007, Jelic et al. 2008), double log polynomials (Wang et al. 2006), and non-parametric techniques (Harker et al. 2009).”